Dispenser having piezoelectric elements and method of operation

ABSTRACT

A dispenser is provided. The dispenser has a reservoir for storing a liquid or solid material. The dispenser may have a piezoelectric valve or pump located in an opening of the reservoir for regulating dispensing of the material. Alternatively, the dispenser may have a piezoelectric inchworm that directly or indirectly propels the material against or out of the opening. The opening may deposit the material directly or indirectly on the surface of an animal, or under the animal&#39;s skin. The dispenser also has means for being attached to the surface of the animal. Alternatively, the dispenser may be placed inside the animal.

FIELD OF THE INVENTION

[0001] The invention relates to a dispenser for small quantities of liquids or solids, in particular a dispenser having one or more piezoelectric elements regulating the rate of dispensation.

BACKGROUND OF THE INVENTION

[0002] Currently there are various methods used in control of pests on large domestic animals such as livestock. Commonly employed methods of pest control include ear tags or tapes, sprays and dusts, and back rubbers and dust bags.

[0003] Ear tags or tapes are pesticide-impregnated materials which are attached to animals by piercing the ear with a sharp post and corresponding locking receptacle or with adhesive. The pesticide slowly leaches from the carrier material and is deposited to the animal. The animal will then spread the material by moving its head from side to side and by rubbing alongside other animals.

[0004] This method of pesticide application tends to have a diminishing effect through its life cycle as the pesticide level eventually runs low enough that sub-lethal amounts of pesticide are deposited on the animal. This poses a serious problem, as sub-lethal applications of pesticide will allow pests to build a tolerance to the pesticide. Future generations of pests may subsequently become immune to what were once lethal exposures to the pesticide.

[0005] Sprays, dusts, and pour-on applications of pesticide involve the manual application of pesticide to the animal's back. Although this method can be effective, it requires additional herding and handling and may not be practical for large ranches or for free-range cattle.

[0006] Back rubbers and dust bags impregnated or filled with pesticide and suspended in a pasture in proximity to a salt lick, water supply or place where the animals are known to rest. The animals will make contact with the device in the normal course of their routine. In addition, the dust bag or back rubber may be located in a gateway which leads to a salt lick or water supply and which forces the animal to contact the device. Again, this method of insecticide application can be effective, but may not be practical for certain situations such as large ranches or free-range cattle.

[0007] It would be desirable to have an application method and dispenser that is capable of dosing a repeatable, prolonged, and lethal application of pesticide to an animal with no gradual decline, but rather, a sudden and complete cessation of exposure, and does not require further herding, handling or contact with the animal.

BRIEF SUMMARY OF THE INVENTION

[0008] A dispenser is provided. The dispenser has a reservoir for storing a liquid or solid material. The dispenser may have a piezoelectric valve or pump located in an opening of the reservoir for regulating dispensing of the material. Alternatively, the dispenser may have a piezoelectric inchworm that directly or indirectly propels the material against or out of the opening. The opening may deposit the material directly or indirectly on the surface of an animal, or under the animal's skin or into the gastro-intestinal tract. The dispenser also may have means for being attached to the surface of the animal. Alternatively, the dispenser may be placed inside the animal.

DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is an exploded view of a first embodiment of the invention.

[0010]FIG. 2 is a side view of a second embodiment of the invention.

[0011]FIGS. 3-7 are cross sectional views of a third embodiment of the invention.

[0012]FIGS. 8-10 are cross sectional views of a fourth embodiment of the invention.

[0013]FIGS. 11-13 are cross sectional views of a fifth embodiment of the invention.

[0014]FIG. 14 is a perspective view of the first embodiment.

[0015]FIG. 15 is an exploded view of the lower section of the first embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0016] The device has a reservoir containing a material to be dispensed. The device also has one or more piezoelectric elements that act as a pump or as a valve to deliver prescribed and discrete measures of liquid or solid material. The piezoelectric elements may work in concert with other materials such as metal, plastic, ceramics, composite materials, etc. to form the complete pump/valve assembly. In addition, the piezoelectric element is coupled with an electronics array to control dose timing and actuation frequency. The electronics array will control dose timing and actuation frequency by controlling the supply of electrical energy to the piezoelectric element. There are several known methods for applying piezoelectric elements to fluid/liquid transfer, such as those used in some types of inkjet printers.

[0017] The dispenser may be designed to be attached to the surface of an animal, typically a domestic animal, in which case it will include an attachment means for maintaining the dispenser in position. Attachment means such as tissue piercing posts and grommets, tapes, adhesives, collars, harnesses, clamps, and staples or other means may be used.

[0018] The reservoir may be designed as a permanent component of the overall assembly or it may be removable and replaceable. In either case, the piezoelectric pump/valve will be coupled to the reservoir and the pesticide or other material will be transferred from the reservoir to the exterior of the device and eventually be deposited on the animal. The piezoelectric element may be adjacent to the reservoir or in the reservoir including in an opening of the reservoir.

[0019] The reservoir may include a one-way valve to allow air to enter the system as the pesticide or other material is transferred from the reservoir. In another embodiment, the reservoir may include an open cell foam sponge which will serve to keep the system primed by means of capillary action. The sponge will work in concert with a vent which is open to atmosphere. This technology is commonly applied to inkjet printing cartridges. In another embodiment, the reservoir may include a collapsible, flexible bladder to avoid drawing a vacuum as the pesticide or other material is transferred from the reservoir. The bladder design will also eliminate the entry of air to the liquid, which may disrupt the transfer of the pesticide or other material from the reservoir. Similarly, the reservoir may be designed along the lines of a syringe to accomplish the same task. As the pesticide or other material is transferred from the reservoir, the syringe piston will move to maintain a constant and predictable system pressure without the introduction of air to the liquid. In another embodiment, the device may dispense under vacuum. In this embodiment the piezoelectric pump or valve may be capable of dispensing the liquid as the system pulls a vacuum condition, eliminating the need for venting the reservoir.

[0020] In one embodiment the piezoelectric element is a valve or pump located in an opening of the reservoir. FIG. 1 shows an example of this embodiment. The dispenser 10 has a reservoir 12 containing the material to be dispensed. The device 14 has a piezoelectric pump or valve 14 located inside to regulate the flow of the material being dispensed. The embodiment illustrated in FIG. 1 has a means for attaching the dispenser to the surface of an animal. In this case, the means comprises a post 16 which is meant to be removed from the device and placed through a piercing in the animal, for example in the animal's ear. Tape 11 in this embodiment is a nonconductive tape that covers one of the terminals of an internal battery. The tape is attached to post 16 so that when the post is removed from the device, the tape is also removed, allowing the internal battery to supply power to the piezoelectric element. After the post is passed through the piercing, locking ring 18 receives the end of the post to secure the dispenser in place.

[0021]FIG. 15 shows the lower section of the device 10 in an exploded view. Tape 11 is shown separated from post 16. The post is fit to battery cover 23 when the device is assembled. Contacts 19 connect battery 13 to electronics 15. As mentioned above, when post 16 is removed, tape 11 is also removed, allowing a circuit between battery 13 and electronics 15 to be completed. The electronics control piezoelectric element 14, which has piezoelectric contacts 25 and piezoelectric stack 27. The electronics are contained in and the piezoelectric element is mounted on electronics housing 27. Absorbent material 21 is also mounted on the electronics housing in the completed device. O-ring 17 allows a tight seal between the battery cover and the electronics housing.

[0022] In one embodiment the piezoelectric element is located in or adjacent to either the reservoir or a chamber in fluid communication with the reservoir. By pulsing current through the piezoelectric element it is possible to expand the element, thereby reducing the space in the reservoir or chamber and forcing a small amount of liquid out of the reservoir or chamber. By pulsing current at a high frequency it is possible to expel a large number of droplets of fluid from the opening. FIG. 2 shows an example of this embodiment. The dispenser has a reservoir 12 having an opening 14. Piezoelectric element 20 expands and contracts as voltage is pulsed through it, causing it to press and release against flexible wall 22. This causes droplets or particles of material 24 to pass through opening 14. The illustrated embodiment also shows optional inlet 24 and optional filter 27 (26 is an o-ring which is used to couple the piezo stack to the reservoir.) An additional container holding material to be dispensed may be connected to reservoir 12 via inlet 24. In such cases it may be desirable to interpose a filter 26 between the inlet 24 and the opening 14 to prevent opening 14 from being clogged by environmental contamination.

[0023]FIG. 3 shows a close-up detail of inlet 24. The inlet would typically contain an o-ring 26 to firmly seat an additional container. FIGS. 4 and 5 are schematic diagrams of a an additional container suitable for use in the present invention. The container 28 contains material 30 to be passed into the reservoir. The container has an opening 32 in wall 34 with means to couple to inlet 24 of dispenser 10. The illustrated container also contains an internal capillary action means consisting of an optional plate or filter 36 disposed adjacent to wall 34, defining a capillary channel 36 between the plate or filter 36 and the wall 34. The optional plate or filter or disc 36 may be used when the material 30 is a liquid material. This capillary channel ensures that if the container is inverted so that the material falls away from opening 32, a small amount of the liquid material will remain in the capillary channel 36. This is useful to reduce the likelihood of reservoir 12 emptying of material and becoming filled with air, as such an event could disrupt the proper pumping function of the piezoelectric element. In another embodiment, a different internal capillary action means could be used, such as a series of grooves or small passages leading directly to the inlet orifice of the piezoelectric element.

[0024] The device may also incorporate piezoelectric inchworm technology to eject a material from an element such as a syringe. In addition, the inchworm device could be used to advance a solid material through the end of a tube or similar device. Piezoelectric inchworm devices are comprised of several piezoelectric elements, which work together to produce a mechanical movement of the piezoelectric elements in a tube or along a rod or similar component. Alternatively, the piezoelectric elements may remain stationary while causing movement of another element such as a rod.

[0025]FIGS. 6 through 10 illustrate the operation of an inchworm device having ring-shaped piezoelectric elements 40, 42, 44 shown in cross-section operating to move the inchworm along a rod 46. Elements numbered 40 and 42 expand and contract radially with respect to the rod, while elements 44 expand and contract axially with respect to the rod. In FIG. 6 elements 40 are contracted, elements 44 are expanded, and elements 42 are expanded to clamp against rod 46. FIG. 7 demonstrates the next step, in which elements 44 contract, pulling elements 40 toward elements 42. FIG. 8 shows the succeeding step, in which elements 40 expand to clamp against rod 46. FIG. 9 shows the assembly after elements 42 contract, releasing their grip on rod 46, and elements 44 expand, moving elements 42 away from elements 40. In FIG. 10 elements 42 once again expand to clamp on rod 46. The cycle repeats as elements 40 contract to release their grip on the rod, resulting in the situation as shown in FIG. 6. Of course, if either elements 40 or 42 were fixed in place against a stationary surface, then the same process could be used to impart axial movement to a movable rod rather than moving the inchworm along a fixed rod. Furthermore, it would be possible to operate the inchworm using a set of piezoelectric elements adjacent to a rod, rather than ring-shaped elements as shown in FIGS. 6 through 10.

[0026]FIGS. 11 through 13 show another embodiment of the inchworm, in which the inchworm has piezoelectric elements 48, 50, and 52 which move through a tubular space defined by walls 54. Elements 48 and 50 expand and contract radially to fit against the walls 54 of the space, while element 52 expands axially along the direction of movement. FIG. 11 shows element 48 expanded against walls 54, element 50 contracted to move freely, and element 52 contracted. FIG. 12 shows the situation after element 50 expands to fit against walls 54, and FIG. 13 shows the situation after element 48 contracts to release its grip on walls 54 and element 52 expands to move element 48 away from element 50. Following these steps, element 48 would expand again, element 50 would contract to release its grip on walls 54, and element 52 would contract again, at which point the assembly is returned to the configuration shown in FIG. 11, but displaced in the direction of travel.

[0027] In another embodiment, the device may be entirely or partially implanted in an animal in a known manner in order to dose pesticides, therapeutic agents, growth hormones, medicines, drugs, etc. If the animal is a ruminant, the entire device may also be deposited to the animal's rumen with a balling gun. Intraruminal devices for dispensing drugs, medicine, hormones, etc. are disclosed in co-pending application Ser. No. 10/141,300, the contents of which are incorporated herein in their entirety. Such devices generally contain a housing with externally mounted retention device such as a pair of plastic “wings”, or else are weighted to prevent their being passed out of the rumen. The device may also be attached to the animal with only a small portion of the device implanted under the skin of the animal to act as a passage for the dosing of a desired material.

[0028] The device can dose a discrete amount of material on demand, on a prescribed timed interval or it may dose continuously and indefinitely over an extended time period until the insecticide or other material is exhausted.

[0029] In addition, since the primary delivery is not through diffusion and is not dependent on high solubility of a parasiticide in a polymer matrix, the fluid utilized in the present invention can be expanded to include previously unusable parasiticides and still include compounds previously dissolved in polymer matrices. These include, but are not limited to various avermectins, benzimidazoles, milbemycins, carbamates, organophosphates, phenylpyrazoles, amidines, insect growth regulators, juvenile hormones, nicotinoids, pyrroles and naturalytes (i.e., the spinosyn family). Representative compounds may include abamectin, doramectin, eprinomectin, selamectin, alphamethrin, amitraz, coumaphos, ivermectin, deltamethrin, cyhalothrin, diazinon, cyromazine, cypermethrin, milbemycin, cyfluthrin, cyloprothrin, famphur, fenthion, fenvalerate, flucythrinate, flumethrin, fipronil, hexaflumaron, imidacloprid, lindane, lufenuron, malathion, methoprene, metriphonate, moxidectin, permethrin, pyrethrin, pyrethrum, phomet, pirimiphos, chlorvinphos, rotenone, propetamphos, tetrachlorvinphos, zetacypermethrin, chlorpyrifos and spinosad, among others.

[0030] In another embodiment, the actuation of the device may be controlled by a centrally located RF (radio frequency) transponder. Each device in this embodiment will incorporate a RF receiver which will allow an operator to transmit instructions to the electronics array. This RF technology could be used to deliver insecticide or other materials on demand or it could be used to change the program, dose frequency, dose amount, rate of delivery, etc. It would also be possible to use the RF signal as the power source for the device, thus greatly reducing the weight by avoiding the use of batteries.

[0031] The device may be activated initially by the user in a number of ways. In one embodiment, the user may remove an insulating strip located between an electrical contact and battery or between two electrical contacts. The strip may be removed by attaching it to an integral component of the device, such as a piercing post, such that any attempt to use the post to mount the device would necessarily force the user to remove the strip. The strip may also be attached to the packaging of the device. As the device is removed from the package, the strip is pulled out and the device is activated. In another embodiment, the device may be activated with a push button or a similar device. In another embodiment, the device may be delivered to the user with an integral part, such as the piercing post, inserted into the device, such that the integral part holds a circuit in the open position. When the user removes the integral part prior to making use of the device, the circuit would close. In the alternative, the part may make momentary contact with a circuit to initiate a pre-programmed response of activating the device.

[0032] In another embodiment, a photovoltaic cell or similar device may be used to activate the device. The device may be activated as it is removed from its packaging and exposed to light. The device may be activated as a strip covering the photovoltaic cell or similar device is removed and exposed to light. The device may be activated as an integral component such as the male piercing post is removed from a section of the device to attach the device to an animal. The piercing post could be situated such that it covers the photovoltaic cell until it is removed for use.

[0033] The device may be activated as the piercing post is seated to the retention grommet. This action may complete a circuit or break a circuit or make momentary contact to initiate activation. The device may also be activated with a magnetic reed switch and a magnetic application tool.

[0034] The device may be powered with a battery or photovoltaic device and a voltage converter. In another embodiment, the device could be powered with another piezoelectric element such as a bender. The bender could be actuated through movement from the animal or from the animal's pulse and the produced voltage could be stored. The stored energy could then be used to power the piezoelectric element and associated electronics that control the pump/valve assembly. In another embodiment, the device could be powered by the animal's body temperature and a thermoelectric device or thermoelectric pile to generate a current. The produced current could be stored. The stored energy could then be used to power the piezoelectric element and associated electronics that control the pump/valve assembly.

[0035] In another embodiment, the device could be powered with a device similar to a self-winding watch mechanism where the mechanical energy derived from the concentric motion of the device is converted to electrical energy and stored. The stored energy could then be used to power the piezoelectric element and associated electronics that control the pump/valve assembly.

[0036] The pesticide or other material may be transferred directly to the surface of the animal, to its skin or fur. Another embodiment would direct the pesticide or other material to an absorbent material, sponge, felt, cloth or other absorbent or porous material in proximity to the animal's skin or fur. The material will be such that it can retain the liquid pesticide or other material without a measurable or significant portion being released in droplet form and falling to the ground. Through the animal's normal movements, the liquid would be rubbed off to the animal's skin or far. In another embodiment, the external surface of the device would have an external capillary action means such as a series of grooves molded adjacent the outlet of the piezoelectric pump or valve. These grooves would capture and retain the expelled liquid on the exterior surface of the device, allowing it to eventually contact the animal. The capillary action means may be used in conjunction with the absorbent material, or by itself Another embodiment would direct the pesticide or other material to a secondary and exterior reservoir or surface of the device, which would allow the insecticide to collect or pool and eventually roll onto the animal. The secondary reservoir or surface will be located such that there is a high probability that the collected pool of pesticide or other material will make contact with the animal and not be lost by dropping to the ground.

[0037] Once the pesticide or other material has reached the animal, it is spread further through the animal's normal movement and interaction with other animals. As the animal moves it head from side to side and rubs along other animals, the pesticide or other material is spread along the entire length of the animal.

[0038] While the device has been discussed in the context of large domestic animals such as ruminants, it would be equally suitable for use with smaller domestic animals, such as companion animals.

[0039] Although the preferred embodiments of the invention have been shown and described, it should be understood that various modifications and changes may be resorted to without departing from the scope of the invention as disclosed and claimed herein. 

We claim:
 1. A dispenser for dispensing a material comprising a reservoir, the reservoir containing a material to be dispensed, the reservoir having an opening, a piezoelectric element disposed adjacent to the reservoir or in the reservoir, the piezoelectric element being a piezoelectric pump or piezoelectric valve, an electronics array for controlling electrical energy supplied to the piezoelectric element, thereby regulating the flow of the material out of the reservoir, a power source for providing electrical energy to the electronic array and piezoelectric element, and an attachment means for attaching the dispenser to the surface of an animal.
 2. A dispenser according to claim 1, further comprising an internal capillary action means adjacent the piezoelectric pump or piezoelectric valve, the internal capillary action means being selected from the group consisting of a plate, a filter of fibrous or porous material, a disc, and a series of grooves or small passages.
 3. The dispenser according to claim 1, wherein the material is a pesticide.
 4. The dispenser according to claim 1, wherein the material is a therapeutic agent.
 5. A dispenser according to claim 1, wherein the dispenser further comprises a radio frequency transponder allowing communication between an operator and the electronics array.
 6. A dispenser according to claim 1, wherein the power source is selected from the group consisting of a battery, a photovoltaic device, a piezoelectric bender, a thermoelectric generator, a capacitive device, or a device for converting mechanical energy to electrical energy.
 7. A dispenser according to claim 1, wherein the attachment means is selected from the group consisting of tissue piercing posts and grommets, tapes, adhesives, collars, harnesses, clamps, and staples.
 8. A dispenser according to claim 1, wherein the piezoelectric element is capable of dispensing the liquid as the system pulls a vacuum condition.
 9. A dispenser according to claim 1, wherein the reservoir further comprises a one-way valve, the one-way valve allowing air to enter the reservoir as the material is dispensed.
 10. A dispenser according to claim 1, wherein the reservoir further comprises an inlet, the dispenser further comprising an additional container, the additional container holding additional material to be dispensed.
 11. A dispenser according to claim 1, further comprising an absorbent or porous material in communication with the opening, the absorbent or porous material being in proximity to the animal's skin or fur when the dispenser is attached to the animal.
 12. A dispenser according to claim 1, further comprising an external capillary means, the external capillary means comprising a series of grooves molded on the exterior of the dispenser adjacent the piezoelectric element.
 13. A dispenser according to claim 1, further comprising a secondary reservoir in communication with the opening for receiving liquid material dispensed through the opening, the secondary reservoir having an opening located such that there is a high probability that liquid material collected in the secondary reservoir will exit through the opening and make contact with the animal.
 14. A dispenser according to claim 1, further comprising an activating means.
 15. A dispenser according to claim 14, wherein the activating means comprises two electrical contacts and an insulating strip disposed between the contacts, whereby removal of the strip closes a circuit by allowing the contacts to touch each other.
 16. A dispenser according to claim 15, wherein the insulating strip is attached to an integral part of the dispenser, whereby use of the device will necessitate removal of the strip from between the contacts.
 17. A dispenser according to claim 14, wherein the activating means comprises a push button.
 18. A dispenser according to claim 14, wherein the attachment means comprises a piercing post and a grommet, and the activating means comprises an electrical circuit disposed in the grommet, whereby insertion of the post into the grommet signals the device to activate by completing the circuit or by breaking the circuit.
 19. A dispenser according to claim 14, wherein the activating means comprises a magnetic reed switch.
 20. A dispenser for dispensing a material in the rumen of an animal, comprising a reservoir, the reservoir containing a material to be dispensed, the reservoir having an opening, a piezoelectric element disposed adjacent to the reservoir, the piezoelectric element being a piezoelectric pump or piezoelectric valve, an electronics array for controlling electrical energy supplied to the piezoelectric element, thereby regulating the flow of the material out of the reservoir, a power source for providing electrical energy to the control means and piezoelectric element, and a retention means for retaining the dispenser in the rumen of the animal.
 21. A dispenser according to claim 20, wherein the retention means is an externally mounted structure or is an internally mounted weight or the weight of the assembled device itself.
 22. A method of dispensing liquid comprising providing a dispenser, the dispenser comprising a reservoir, the reservoir containing a material to be dispensed, the reservoir having an opening, a piezoelectric element disposed adjacent to the reservoir, the piezoelectric element being a piezoelectric pump or piezoelectric valve, an electronics array for controlling electrical energy supplied to the piezoelectric element, thereby regulating the flow of the material out of the reservoir, a power source for providing electrical energy to the control means and piezoelectric element, and an attachment means for attaching the dispenser to the surface of an animal, and attaching the dispenser to the surface of the animal.
 23. The method according to claim 22, wherein when the dispenser is attached to the surface of the animal a small portion of the device is implanted under the skin of the animal to allow dispensing of the material under the animal's skin.
 24. A dispenser comprising a reservoir, an outlet in communication with the reservoir, and a piezoelectric inchworm device adjacent to the reservoir, the piezoelectric inchworm comprising a first and a second piezoelectric element having axes of expansion or contraction substantially parallel to each other, the piezoelectric inchworm device further comprising a third piezoelectric element connected to and between the first and second piezoelectric element and having an axis of expansion and contraction substantially perpendicular to the axes of expansion and contraction of the first and second piezoelectric elements.
 25. The dispenser according to claim 24, further comprising means for attaching the dispenser to an animal.
 26. The dispenser according to claim 24, further comprising a charge of pesticide disposed in the reservoir.
 27. The dispenser according to claim 24, further comprising a therapeutic agent disposed in the reservoir.
 28. The dispenser according to claim 27, further comprising a means for retaining the dispenser in the rumen of an animal.
 29. The dispenser according to claim 24, further comprising an absorbent material adjacent to the outlet.
 30. The dispenser according to claim 24, further comprising an electronics array for controlling the piezoelectric inchworm device.
 31. The dispenser according to claim 30, further comprising a radio frequency receiver for receiving instructions to the electronics array.
 32. The dispenser according to claim 24, further comprising a power supply selected from the group consisting of a battery, a photovoltaic device, a piezoelectric bender, a thermoelectric device, clockwork, and combinations thereof.
 33. A method of dispensing liquid comprising providing a dispenser, the dispenser comprising a reservoir, the reservoir containing a liquid material to be dispensed, the reservoir having an opening, a piezoelectric element disposed adjacent to or in the reservoir, the piezoelectric element being a piezoelectric pump or piezoelectric valve, an electronics array for controlling electrical energy supplied to the piezoelectric element, thereby regulating the flow of the material out of the reservoir, a power source for providing electrical energy to the control means and piezoelectric element, and implanting the dispenser in a domestic animal. 